Single-cell measurements of the contributions of cytosolic Na+ and K+ to cell salt tolerance

Carden, David E, Walker, David J, Flowers, Timothy J and Miller, Anthony J (2003) Single-cell measurements of the contributions of cytosolic Na+ and K+ to cell salt tolerance. Plant Physiology, 131. pp. 676-683. ISSN 0032-0889

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Abstract

Ion concentrations in the roots of two barley (Hordeum vulgare) varieties that differed in NaCl tolerance were compared after exposure to NaCl. Triple-barreled H_-, K_-, and Na_-selective microelectrodes were used to measure cytosolic activities of the three ions after 5 and 8 d of NaCl stress. In both varieties of barley, it was only possible to record successfully from root cortical cells because the epidermal cells appeared to be damaged. The data show that from the 1st d of full NaCl stress, there were differences in the way in which the two varieties responded. At 5 d, the tolerant variety maintained a 10-fold lower cytosolic Na_ than the more sensitive variety, although by 8 d the two varieties were not significantly different. At this time, the more tolerant variety was better at maintaining root cytosolic K_ in the high-NaCl background than was the more sensitive variety. In contrast to earlier work on K_-starved barley (Walker et al., 1996), there was no acidification of the cytosol associated with the decreased cytosolic K_ activity during NaCl stress. These single-cell measurements of cytosolic and vacuolar ion activities allow calculation of thermodynamic gradients that can be used to reveal (or predict) the type of active transporters at both the plasma membrane and tonoplast.

Item Type: Article
Additional Information: The measurement of cytoplasmic ion concentrations in plants is extremely difficult. This paper reports values obtained using technically demanding triple-barrelled micro-electrodes to answer a fundamental problem of salt tolerance. Results from a doctoral thesis (Carden) co-supervised by Flowers and Miller and based on earlier work of Flowers.
Schools and Departments: School of Life Sciences > Evolution, Behaviour and Environment
Depositing User: Tim Flowers
Date Deposited: 06 Feb 2012 20:25
Last Modified: 22 Mar 2012 08:56
URI: http://sro.sussex.ac.uk/id/eprint/25885
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